From 266fa2b22294909ddf6e7d2f8acfe07adf9fd978 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 24 Sep 2015 11:24:18 -0300 Subject: [PATCH 1/3] perf probe: Use existing routine to look for a kernel module by dso->short_name We have map_groups__find_by_name() to look at the list of modules that are in place for a given machine, so use it instead of traversing the machine dso list, which also includes DSOs for userspace. When merging the user and kernel DSO lists a bug was introduced where 'perf probe' stopped being able to add probes to modules using its short name: # perf probe -m usbnet --add usbnet_start_xmit usbnet_start_xmit is out of .text, skip it. Error: Failed to add events. # With this fix it works again: # perf probe -m usbnet --add usbnet_start_xmit Added new event: probe:usbnet_start_xmit (on usbnet_start_xmit in usbnet) You can now use it in all perf tools, such as: perf record -e probe:usbnet_start_xmit -aR sleep 1 # Reported-by: Wang Nan Acked-by: Masami Hiramatsu Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Fixes: 3d39ac538629 ("perf machine: No need to have two DSOs lists") Link: http://lkml.kernel.org/r/20150924015008.GE1897@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-event.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index eb5f18b75402..c6f9af78f6f5 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -270,12 +270,13 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso) int ret = 0; if (module) { - list_for_each_entry(dso, &host_machine->dsos.head, node) { - if (!dso->kernel) - continue; - if (strncmp(dso->short_name + 1, module, - dso->short_name_len - 2) == 0) - goto found; + char module_name[128]; + + snprintf(module_name, sizeof(module_name), "[%s]", module); + map = map_groups__find_by_name(&host_machine->kmaps, MAP__FUNCTION, module_name); + if (map) { + dso = map->dso; + goto found; } pr_debug("Failed to find module %s.\n", module); return -ENOENT; From 597ee40722bf05195f91a41e88e15b79bdab152c Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 24 Sep 2015 13:05:21 +0300 Subject: [PATCH 2/3] perf intel-pt: Remove no_force_psb from documentation no_force_psb was dropped as a late change to the kernel driver. Consequently, remove it from the documentation. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443089122-19082-2-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/intel-pt.txt | 15 --------------- 1 file changed, 15 deletions(-) diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt index 4a0501d7a3b4..c94c9de3173e 100644 --- a/tools/perf/Documentation/intel-pt.txt +++ b/tools/perf/Documentation/intel-pt.txt @@ -364,21 +364,6 @@ cyc_thresh Specifies how frequently CYC packets are produced - see cyc CYC packets are not requested by default. -no_force_psb This is a driver option and is not in the IA32_RTIT_CTL MSR. - - It stops the driver resetting the byte count to zero whenever - enabling the trace (for example on context switches) which in - turn results in no PSB being forced. However some processors - will produce a PSB anyway. - - In any case, there is still a PSB when the trace is enabled for - the first time. - - no_force_psb can be used to slightly decrease the trace size but - may make it harder for the decoder to recover from errors. - - no_force_psb is not selected by default. - new snapshot option ------------------- From b5cabbcbd157a4bf5a92dfc85134999a3b55342d Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 24 Sep 2015 13:05:22 +0300 Subject: [PATCH 3/3] perf tools: Fix copying of /proc/kcore A copy of /proc/kcore containing the kernel text can be made to the buildid cache. e.g. perf buildid-cache -v -k /proc/kcore To workaround objdump limitations, a copy is also made when annotating against /proc/kcore. The copying process stops working from libelf about v1.62 onwards (the problem was found with v1.63). The cause is that a call to gelf_getphdr() in kcore__add_phdr() fails because additional validation has been added to gelf_getphdr(). The use of gelf_getphdr() is a misguided attempt to get default initialization of the Gelf_Phdr structure. That should not be necessary because every member of the Gelf_Phdr structure is subsequently assigned. So just remove the call to gelf_getphdr(). Similarly, a call to gelf_getehdr() in gelf_kcore__init() can be removed also. Committer notes: Note to stable@kernel.org, from Adrian in the cover letter for this patchkit: The "Fix copying of /proc/kcore" problem goes back to v3.13 if you think it is important enough for stable. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1443089122-19082-3-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol-elf.c | 33 ++++++++++++--------------------- 1 file changed, 12 insertions(+), 21 deletions(-) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index f78ea3dc4c08..475d88d0a1c9 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -1271,8 +1271,6 @@ out_close: static int kcore__init(struct kcore *kcore, char *filename, int elfclass, bool temp) { - GElf_Ehdr *ehdr; - kcore->elfclass = elfclass; if (temp) @@ -1289,9 +1287,7 @@ static int kcore__init(struct kcore *kcore, char *filename, int elfclass, if (!gelf_newehdr(kcore->elf, elfclass)) goto out_end; - ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); - if (!ehdr) - goto out_end; + memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); return 0; @@ -1348,23 +1344,18 @@ static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, u64 addr, u64 len) { - GElf_Phdr gphdr; - GElf_Phdr *phdr; + GElf_Phdr phdr = { + .p_type = PT_LOAD, + .p_flags = PF_R | PF_W | PF_X, + .p_offset = offset, + .p_vaddr = addr, + .p_paddr = 0, + .p_filesz = len, + .p_memsz = len, + .p_align = page_size, + }; - phdr = gelf_getphdr(kcore->elf, idx, &gphdr); - if (!phdr) - return -1; - - phdr->p_type = PT_LOAD; - phdr->p_flags = PF_R | PF_W | PF_X; - phdr->p_offset = offset; - phdr->p_vaddr = addr; - phdr->p_paddr = 0; - phdr->p_filesz = len; - phdr->p_memsz = len; - phdr->p_align = page_size; - - if (!gelf_update_phdr(kcore->elf, idx, phdr)) + if (!gelf_update_phdr(kcore->elf, idx, &phdr)) return -1; return 0;